Perhaps, a car hit him. In pain and fear, the cat crawled into the bushes, but when he realized things were dire, he mustered his last bit of strength and reached out to humans. His hind legs were broken, and the wounds had become infected.
Yashka has learned to move and doesn't consider the absence of his hind legs a problem or misfortune. He finds joy in people, other cats, and life itself. This clever and affectionate kitty first gets used to new people, and when he trusts them, he purrs, snuggles, and kisses.